Conventionally, inorganic photoreceptors comprised of inorganic photoconductive materials such as selenium, cadmium sulfide, amorphous silicon and the like have been employed. However, said inorganic photoreceptors have had many problems such that the production is complicated, many of them exhibit toxicity, and are not preferred from the viewpoint of environmental protection as well as health.
Accordingly, instead of the aforementioned inorganic photoconductors, research and development have been increasingly carried out for organic photoreceptors comprised of organic photoconductive materials, which are not toxic, are easily produced, and exhibit wide option for the selection. Of the aforementioned organic photoreceptors, a function separation type photoreceptor comprised of a charge generating layer (CGL) comprising a charge generating material and a charge transport layer (CTL) comprising a charge transport material (CTM) in this order is now in main stream. Further, digital imaging has been progressed in which an image is formed on said photoreceptor employing, for example, light from a light emitting diode, a laser beam, or the like. Being based on this, enhancement in image quality has been demanded.
However, the aforementioned organic photoreceptors have had problems in which the mechanical abrasion resistance is small and repeated charging and exposure readily result in fatigue deterioration, compared to inorganic photoreceptors.
Thus, as means to enhance the abrasion resistance of the aforementioned organic photoreceptor (hereinafter simply referred to as photoreceptor), are known methods in which a the polymerization degree of a binder resin is increased, filler is added to a binder resin, a solid lubricating agent such as polytetrafluoroethylene (PTFE) is added to the surface of a photoreceptor and a friction coefficient between the photoreceptor and the cleaning blade as a cleaning means is decreased, and the like.